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4387758 Apr 8, 2014
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@zacharyw @kikito
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--
-- Adapted from
-- Tweener's easing functions (Penner's Easing Equations)
-- and http://code.google.com/p/tweener/ (jstweener javascript version)
--
--[[
Disclaimer for Robert Penner's Easing Equations license:
TERMS OF USE - EASING EQUATIONS
Open source under the BSD License.
Copyright © 2001 Robert Penner
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
* Neither the name of the author nor the names of contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
]]
-- For all easing functions:
-- t = elapsed time
-- b = begin
-- c = change == ending - beginning
-- d = duration (total time)
local pow = math.pow
local sin = math.sin
local cos = math.cos
local pi = math.pi
local sqrt = math.sqrt
local abs = math.abs
local asin = math.asin
local function linear(t, b, c, d)
return c * t / d + b
end
local function inQuad(t, b, c, d)
t = t / d
return c * pow(t, 2) + b
end
local function outQuad(t, b, c, d)
t = t / d
return -c * t * (t - 2) + b
end
local function inOutQuad(t, b, c, d)
t = t / d * 2
if t < 1 then
return c / 2 * pow(t, 2) + b
else
return -c / 2 * ((t - 1) * (t - 3) - 1) + b
end
end
local function outInQuad(t, b, c, d)
if t < d / 2 then
return outQuad (t * 2, b, c / 2, d)
else
return inQuad((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inCubic (t, b, c, d)
t = t / d
return c * pow(t, 3) + b
end
local function outCubic(t, b, c, d)
t = t / d - 1
return c * (pow(t, 3) + 1) + b
end
local function inOutCubic(t, b, c, d)
t = t / d * 2
if t < 1 then
return c / 2 * t * t * t + b
else
t = t - 2
return c / 2 * (t * t * t + 2) + b
end
end
local function outInCubic(t, b, c, d)
if t < d / 2 then
return outCubic(t * 2, b, c / 2, d)
else
return inCubic((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inQuart(t, b, c, d)
t = t / d
return c * pow(t, 4) + b
end
local function outQuart(t, b, c, d)
t = t / d - 1
return -c * (pow(t, 4) - 1) + b
end
local function inOutQuart(t, b, c, d)
t = t / d * 2
if t < 1 then
return c / 2 * pow(t, 4) + b
else
t = t - 2
return -c / 2 * (pow(t, 4) - 2) + b
end
end
local function outInQuart(t, b, c, d)
if t < d / 2 then
return outQuart(t * 2, b, c / 2, d)
else
return inQuart((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inQuint(t, b, c, d)
t = t / d
return c * pow(t, 5) + b
end
local function outQuint(t, b, c, d)
t = t / d - 1
return c * (pow(t, 5) + 1) + b
end
local function inOutQuint(t, b, c, d)
t = t / d * 2
if t < 1 then
return c / 2 * pow(t, 5) + b
else
t = t - 2
return c / 2 * (pow(t, 5) + 2) + b
end
end
local function outInQuint(t, b, c, d)
if t < d / 2 then
return outQuint(t * 2, b, c / 2, d)
else
return inQuint((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inSine(t, b, c, d)
return -c * cos(t / d * (pi / 2)) + c + b
end
local function outSine(t, b, c, d)
return c * sin(t / d * (pi / 2)) + b
end
local function inOutSine(t, b, c, d)
return -c / 2 * (cos(pi * t / d) - 1) + b
end
local function outInSine(t, b, c, d)
if t < d / 2 then
return outSine(t * 2, b, c / 2, d)
else
return inSine((t * 2) -d, b + c / 2, c / 2, d)
end
end
local function inExpo(t, b, c, d)
if t == 0 then
return b
else
return c * pow(2, 10 * (t / d - 1)) + b - c * 0.001
end
end
local function outExpo(t, b, c, d)
if t == d then
return b + c
else
return c * 1.001 * (-pow(2, -10 * t / d) + 1) + b
end
end
local function inOutExpo(t, b, c, d)
if t == 0 then return b end
if t == d then return b + c end
t = t / d * 2
if t < 1 then
return c / 2 * pow(2, 10 * (t - 1)) + b - c * 0.0005
else
t = t - 1
return c / 2 * 1.0005 * (-pow(2, -10 * t) + 2) + b
end
end
local function outInExpo(t, b, c, d)
if t < d / 2 then
return outExpo(t * 2, b, c / 2, d)
else
return inExpo((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inCirc(t, b, c, d)
t = t / d
return(-c * (sqrt(1 - pow(t, 2)) - 1) + b)
end
local function outCirc(t, b, c, d)
t = t / d - 1
return(c * sqrt(1 - pow(t, 2)) + b)
end
local function inOutCirc(t, b, c, d)
t = t / d * 2
if t < 1 then
return -c / 2 * (sqrt(1 - t * t) - 1) + b
else
t = t - 2
return c / 2 * (sqrt(1 - t * t) + 1) + b
end
end
local function outInCirc(t, b, c, d)
if t < d / 2 then
return outCirc(t * 2, b, c / 2, d)
else
return inCirc((t * 2) - d, b + c / 2, c / 2, d)
end
end
local function inElastic(t, b, c, d, a, p)
if t == 0 then return b end
t = t / d
if t == 1 then return b + c end
if not p then p = d * 0.3 end
local s
if not a or a < abs(c) then
a = c
s = p / 4
else
s = p / (2 * pi) * asin(c/a)
end
t = t - 1
return -(a * pow(2, 10 * t) * sin((t * d - s) * (2 * pi) / p)) + b
end
-- a: amplitud
-- p: period
local function outElastic(t, b, c, d, a, p)
if t == 0 then return b end
t = t / d
if t == 1 then return b + c end
if not p then p = d * 0.3 end
local s
if not a or a < abs(c) then
a = c
s = p / 4
else
s = p / (2 * pi) * asin(c/a)
end
return a * pow(2, -10 * t) * sin((t * d - s) * (2 * pi) / p) + c + b
end
-- p = period
-- a = amplitud
local function inOutElastic(t, b, c, d, a, p)
if t == 0 then return b end
t = t / d * 2
if t == 2 then return b + c end
if not p then p = d * (0.3 * 1.5) end
if not a then a = 0 end
local s
if not a or a < abs(c) then
a = c
s = p / 4
else
s = p / (2 * pi) * asin(c / a)
end
if t < 1 then
t = t - 1
return -0.5 * (a * pow(2, 10 * t) * sin((t * d - s) * (2 * pi) / p)) + b
else
t = t - 1
return a * pow(2, -10 * t) * sin((t * d - s) * (2 * pi) / p ) * 0.5 + c + b
end
end
-- a: amplitud
-- p: period
local function outInElastic(t, b, c, d, a, p)
if t < d / 2 then
return outElastic(t * 2, b, c / 2, d, a, p)
else
return inElastic((t * 2) - d, b + c / 2, c / 2, d, a, p)
end
end
local function inBack(t, b, c, d, s)
if not s then s = 1.70158 end
t = t / d
return c * t * t * ((s + 1) * t - s) + b
end
local function outBack(t, b, c, d, s)
if not s then s = 1.70158 end
t = t / d - 1
return c * (t * t * ((s + 1) * t + s) + 1) + b
end
local function inOutBack(t, b, c, d, s)
if not s then s = 1.70158 end
s = s * 1.525
t = t / d * 2
if t < 1 then
return c / 2 * (t * t * ((s + 1) * t - s)) + b
else
t = t - 2
return c / 2 * (t * t * ((s + 1) * t + s) + 2) + b
end
end
local function outInBack(t, b, c, d, s)
if t < d / 2 then
return outBack(t * 2, b, c / 2, d, s)
else
return inBack((t * 2) - d, b + c / 2, c / 2, d, s)
end
end
local function outBounce(t, b, c, d)
t = t / d
if t < 1 / 2.75 then
return c * (7.5625 * t * t) + b
elseif t < 2 / 2.75 then
t = t - (1.5 / 2.75)
return c * (7.5625 * t * t + 0.75) + b
elseif t < 2.5 / 2.75 then
t = t - (2.25 / 2.75)
return c * (7.5625 * t * t + 0.9375) + b
else
t = t - (2.625 / 2.75)
return c * (7.5625 * t * t + 0.984375) + b
end
end
local function inBounce(t, b, c, d)
return c - outBounce(d - t, 0, c, d) + b
end
local function inOutBounce(t, b, c, d)
if t < d / 2 then
return inBounce(t * 2, 0, c, d) * 0.5 + b
else
return outBounce(t * 2 - d, 0, c, d) * 0.5 + c * .5 + b
end
end
local function outInBounce(t, b, c, d)
if t < d / 2 then
return outBounce(t * 2, b, c / 2, d)
else
return inBounce((t * 2) - d, b + c / 2, c / 2, d)
end
end
return {
linear = linear,
inQuad = inQuad,
outQuad = outQuad,
inOutQuad = inOutQuad,
outInQuad = outInQuad,
inCubic = inCubic ,
outCubic = outCubic,
inOutCubic = inOutCubic,
outInCubic = outInCubic,
inQuart = inQuart,
outQuart = outQuart,
inOutQuart = inOutQuart,
outInQuart = outInQuart,
inQuint = inQuint,
outQuint = outQuint,
inOutQuint = inOutQuint,
outInQuint = outInQuint,
inSine = inSine,
outSine = outSine,
inOutSine = inOutSine,
outInSine = outInSine,
inExpo = inExpo,
outExpo = outExpo,
inOutExpo = inOutExpo,
outInExpo = outInExpo,
inCirc = inCirc,
outCirc = outCirc,
inOutCirc = inOutCirc,
outInCirc = outInCirc,
inElastic = inElastic,
outElastic = outElastic,
inOutElastic = inOutElastic,
outInElastic = outInElastic,
inBack = inBack,
outBack = outBack,
inOutBack = inOutBack,
outInBack = outInBack,
inBounce = inBounce,
outBounce = outBounce,
inOutBounce = inOutBounce,
outInBounce = outInBounce,
}